The technical specification 3GPP TS 23.203 (version V11.0.1; January 2011) discloses a Policy and Charging Architecture (PCC) used in a telecommunications system, which allows among other things the application of charging and quality of service (QoS) policies to data flows of the data sessions of their users. FIG. 1 (PRIOR ART) illustrates one of the PCC architectures 100 disclosed in 3GPP TS 23.203 (V11.0.1). The PCC architecture 100 comprises these main functional entities: a Home Policy and Charging Rules Function 102 (H-PCRF 102), a Policy and Charging Enforcement Function 104 (PCEF 104), a Gateway 105, and a Traffic Detection Function 106 (TDF 106). Briefly, the PCRF 102 behaves as a Policy Decision Point (PDP), or policy server, which stores user policies and determines which user polices are to be applied in each case. While, the network nodes implementing the PCEF 104 and/or the TDF 106 functionalities actually route data traffic flows to and from end users and behave as Policy Enforcing Points (PEPs) of the user policies. In addition, the PCC architecture 100 comprises an Online Charging System 108 (OCS 108), an Offline Charging System 110 (OFCS 110), a Subscription Profile Repository 112 (SPR 112), an Application Function 114 (AF 114), a V-PCRF 116, and a Bearer Binding and Event Reporting Function 118 (BBERF 118). The contents of the 3GPP TS 23.203 (version V11.0.1; January 2011) are hereby incorporated by reference herein.
In short, when a user terminal (usually referred as User Equipment, UE) initiates a data session through the mobile telecommunication system the PCEF communicates with the PCRF to download the PCEF policy rules (PCC rules) which are to be applied to the data session. The TDF performs Deep Packet Inspection (DPI) for the data flows belonging to the data session. The deep packet inspection includes inspecting the contents of the Internet Protocol (IP) packets of the data flows beyond the so called IP-5 tuples (i.e. beyond, IP origination/destination addresses and ports, and used transport protocol). The TDF based on this inspection then reports the application usage information for the data traffic flows to the PCRF. The PCRF then downloads policy rules to the TDF (as well as to the PCEF) which are to be enforced therein for these data traffic flows. The 3GPP TS 23.203 (version V11.0.1—FIG. 7.2-1) describes the so called “IP-CAN” session establishment, and the signalling interactions among the nodes implementing the aforementioned functions, which allows an end user to establish one or more data traffic flows through the telecommunication system via one or more data bearers.
Whilst the PCRF functionality is usually implemented within a standalone node, the PCEF functionality is usually co-located within an access gateway, such as a Gateway GPRS Support Node (GGSN). In turn, and for performance and efficiency reasons, the TDF node is advantageously implemented as a stand-alone node although their functionalities can be also co-located with a gateway intervening in a communication, such as a GGSN which also implements the PCEF functionalities. For example, the Ericsson product called “SASN” implements among other functions the DPI functionalities and thus it is a candidate to implement the TDF functionality disclosed by the 3GPP TS 23.203 (version V11.0.1).
The basic functionality for the Traffic Detection Function (TDF) is described in the aforementioned 3GPP TS 23.203 (V11.0.1). Aspects related to the TDF functionality, as well as the need for such functionality, are further discussed in the 3GPP TR 23.813 (V0.5.0) (the contents of which are incorporated herein by reference). In short, the need for a TDF stems from the hindsight that the operator of a telecommunication system might be interested in having traffic related policies with regard to certain specific services and that it may not always become aware of the usage of these services by its end users. The TDF and its standardized interworking with a policy server implementing the PCRF functionality addresses this issue and provides service awareness so the operator can enforce e.g. the corresponding charging and/or QoS policies.
In accordance with 3GPP TS 23.203 (V11.0.1), the routing of data packets of an end user's data session through the “Gi” or “SGi” interfaces (e.g. from a gateway, such as a GGSN or a Packet Data Network Gateway (PDN-GW), towards a certain data network) are currently dependent on the Access Point Name (APN) and IP address which are determined when the IP-CAN session of the user is initiated and established (e.g., see FIG. 7.2-1 of 3GPP TS 23.203 referred above, and related flow descriptions). And, during the IP CAN session establishment for a user the APN is selected and an IP address is assigned to the user. So, even prior to any opportunity for a policy decision to be made by the PCRF, the path which the end user packets will follow when establishing data communications with other parties within the data session (e.g. with other user terminals, application servers, etc) has already been predetermined. As a result of this static path determination, the end user's packets may always undergo deep packet inspection performed by a standalone TDF node configured in the data path. This deep packet inspection may be in conflict with the privacy preferences of the end user. Furthermore, using a predetermined way for routing user data packets does not fit well, and does not offer a feasible solution, for network operators willing to deploy and enforce policies based on awareness about access to certain services by their end users which can have an effect, for example, on the charging of the corresponding data flows, and/or on the application of QoS policies for the corresponding data flows.
In short, the main problem is that end users are assigned an APN (e.g. predefined within a Home Subscriber Server (HSS) which stores the profile data of the end user, or requested by an UE) and an IP address (e.g. assigned by a gateway implementing the PCEF functionality) before any dynamic policy decision is made e.g., by the PCRF. Thus, the routing of end user packets is influenced by the APN which may or may not have a TDF deployed. In addition, the assigned IP address within the APN may influence the IP routing when for instance the network design has segmented the IP address space into various IP address pools with different routing/forwarding properties. This IP assignment may result in end user packets being routed towards a TDF in conflict with the User Privacy Policy within the PCRF which may indicate that the consent of the end user has not been given for DPI of their data packets. Accordingly, there has been and is a need to address these problems and other problems associated with the traditional IP CAN session establishment. This need and other needs are satisfied by the present invention.